1. Field of the Invention
The present invention relates to a coupling device and an electronic device.
2. Description of the Related Art
There are various types of cellular phones. For example, Unexamined Japanese Patent Application KOKAI Publication No. 2001-136252 discloses a foldable type which has two casings coupled together by a hinge unit. In addition, there are a straight slide type having two casings coupled to be slidable linearly, and a rotary slide type having two casings coupled to be slidable arcuately.
A foreign matter, such as dust or sands, is likely to enter the clearance of the coupled section of an electronic device including a cellular phone having two casings coupled together. When the two casings are moved with a foreign matter having entered therein, the foreign matter damages the casings and/or the coupled section.